On Wed, 17 Nov 2004 12:31:48 +1300, "Mark" wrote:


I
suppose I was outlining a rule of thumb, perhaps to be used in an emergency
situation, or simply as an exercise to demonstrate such relationships
between the three.

Agreed. It does go, at least ghenerally, to the relationships.
And you'd want to know whether you're in your hemisphere or mine
before you start. :-)



Anyway, after re-reading all of this, I realised I have drifted off-course

May I suggest following the sci.geo.satellite-nav newsgroup
for help with this part of the problem? :-)

and off-topic. Now, back to the radio....

Mark.
Auckland, New Zealand, which is located at 36 degrees, 52 minutes South, 174
degrees, 52 minutes East. And the magnetic variation is currently around 19
degrees, 30 minutes East.